Live-Cell Single RNA Imaging Reveals Bursts of Translational Frameshifting

Ribosomal frameshifting during the translation of RNA is implicated in human disease and viral infection. While previous work has uncovered many details about single RNA frameshifting kinetics in vitro, little is known about how single RNA frameshift in living systems. To confront this problem, we have developed technology to quantify live-cell single RNA translation dynamics in frameshifted open reading frames. Applying this technology to RNA encoding the HIV-1 frameshift sequence reveals a small subset (∼8%) of the translating pool robustly frameshift. Frameshifting RNA are translated at similar rates as non-frameshifting RNA (∼3 aa/s) and can continuously frameshift for more than four rounds of translation. Fits to a bursty model of frameshifting constrain frameshifting kinetic rates and demonstrate how ribosomal traffic jams contribute to the persistence of the frameshifting state. These data provide insight into retroviral frameshifting and could lead to alternative strategies to perturb the process in living cells.

Multicolour single-molecule tracking of mRNA interactions with RNP granules

Ribonucleoprotein (RNP) granules are non-membrane-bound organelles that have critical roles in the stress response1,2, maternal messenger RNA storage3, synaptic plasticity4, tumour progression5,6 and neurodegeneration7-9. However, the dynamics of their mRNA components within and near the granule surface remain poorly characterized, particularly in the context and timing of mRNAs exiting translation. Herein, we used multicolour single-molecule tracking to quantify the precise timing and kinetics of single mRNAs as they exit translation and enter RNP granules during stress. We observed single mRNAs interacting with stress granules and P-bodies, with mRNAs moving bidirectionally between them. Although translating mRNAs only interact with RNP granules dynamically, non-translating mRNAs can form stable, and sometimes rigid, associations with RNP granules with stability increasing with both mRNA length and granule size. Live and fixed cell imaging demonstrated that mRNAs can extend beyond the protein surface of a stress granule, which may facilitate interactions between RNP granules. Thus, the recruitment of mRNPs to RNP granules involves dynamic, stable and extended interactions affected by translation status, mRNA length and granule size that collectively regulate RNP granule dynamics.

Real-time quantification of single RNA translation dynamics in living cells

Although messenger RNA (mRNA) translation is a fundamental biological process, it has never been imaged in real time in vivo with single-molecule precision. To achieve this, we developed nascent chain tracking (NCT), a technique that uses multi-epitope tags and antibody-based fluorescent probes to quantify protein synthesis dynamics at the single-mRNA level. NCT reveals an elongation rate of ~10 amino acids per second, with initiation occurring stochastically every ~30 seconds. Polysomes contain ~1 ribosome every 200 to 900 nucleotides and are globular rather than elongated in shape. By developing multicolor probes, we showed that most polysomes act independently; however, a small fraction (~5%) form complexes in which two distinct mRNAs can be translated simultaneously. The sensitivity and versatility of NCT make it a powerful new tool for quantifying mRNA translation kinetics.

Complete genome sequence of an M1 strain of Streptococcus pyogenes

The 1,852,442-bp sequence of an M1 strain of Streptococcus pyogenes, a Gram-positive pathogen, has been determined and contains 1,752 predicted protein-encoding genes. Approximately one-third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of human disease than any other bacterial species, more than 40 putative virulence-associated genes have been identified. Additional genes have been identified that encode proteins likely associated with microbial "molecular mimicry" of host characteristics and involved in rheumatic fever or acute glomerulonephritis. The complete or partial sequence of four different bacteriophage genomes is also present, with each containing genes for one or more previously undiscovered superantigen-like proteins. These prophage-associated genes encode at least six potential virulence factors, emphasizing the importance of bacteriophages in horizontal gene transfer and a possible mechanism for generating new strains with increased pathogenic potential.

Massive ascites secondary to severe endometriosis

Massive ascites is an unusual association with endometriosis. This case report is of such a condition in an Afro-Jamaican woman. The diagnosis was made at laparotomy and conservative treatment was adopted allowing for retention of reproductive function. Postoperative therapy was Goserelin, a Gonadotropin Releasing Hormone (GnRH) agonist, for six months. This relieved all of her symptoms. However, long term follow-up is needed, as recurrence is possible.

An instrument to measure functional status outcomes for disorders of excessive sleepiness

This article reports the development of the functional outcomes of sleep questionnaire (FOSQ). This is the first self-report measure designed to assess the impact of disorders of excessive sleepiness (DOES) on multiple activities of everyday living. Three samples were used in the development and psychometric analyses of the FOSQ: Sample 1 (n = 153) consisted of individuals seeking medical attention for a sleep problem and persons of similar age and gender having no sleep disorder; samples 2 (n = 24) and 3 (n = 51) were composed of patients from two medical centers diagnosed with obstructive sleep apnea (OSA). Factor analysis of the FOSQ yielded five factors: activity level, vigilance, intimacy and sexual relationships, general productivity, and social outcome. Internal reliability was excellent for both the subscales (alpha = 0.86 to alpha = 0.91) and the total scale (alpha = 0.95). Test-retest reliability of the FOSQ yielded coefficients ranging from r = 0.81 to r = 0.90 for the five subscales and r = 0.90 for the total measure. The FOSQ successfully discriminated between normal subjects and those seeking medical attention for a sleep problem (T157 = -5.88, p = 0.0001). This psychometric evaluation of the FOSQ demonstrated parameters acceptable for its application in research and in clinical practice to measure functional status outcomes for persons with DOES. Thus, the FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to which these abilities are improved by effective treatment of DOES.

The impact of 5-alpha-reductase inhibitors on the number of prostatectomies for benign prostatic hyperplasia

To determine the impact of a 5-alpha-reductase inhibitor on the need for surgical treatment of symptomatic benign prostatic hyperplasia (BPH) in clinical urologic practice, we retrospectively reviewed records of 794 patients treated with pharmacotherapy or surgery (or both). The number of transurethral resections of the prostate (TURPs) performed during the 30 months since introduction of finasteride was compared with the number performed during the 30 months before finasteride became available. The alpha-blockers doxazosin and prazosin were used during both times for the treatment of BPH. Of the 619 patients treated with drugs, 88.5% received finasteride for a mean of 249.6 days. The alpha-blockers, either alone or combined with finasteride, were prescribed for 11.5% of patients for a mean of 179 days. In the 30 months after the introduction of finasteride, 65 patients underwent TURP: 28 of these men had initially received drug therapy. In contrast, 138 TURPs were performed in the 30 months prior to the availability of finasteride. The use of a 5-alpha-reductase inhibitor as primary medical therapy for symptomatic BPH decreased the number of prostatectomies by 52.9% (65 vs 138). This observation warrants corroboration through additional prospective studies.

Pet avian medicine. Sources of information

This article is intended to serve as a guide to sources of information on avians. College and university libraries, abstract and index services, bookstores, journals, and veterinary literature are listed. Avian conferences, computer search services, natural history libraries and museums, and places to obtain video and audio tapes and slides are included.

Effects of long-term neuroleptic use on brain density

Mean density values of the brain in four quadrants were determined for a sample of 16 chronic schizophrenic patients who had received between 0 and 3,000 grams of lifetime neuroleptics. Significant correlations were found between the measures of density in the posterior quadrants of both hemispheres and total lifetime medication usage. Correlations with anterior density were insignificant. Corrections for age and current severity of the disorder (as measured by the Brief Psychiatric Rating Scale) did not alter the significant finding. Possible explanations for the results are discussed as well as their possible implications.